1. David Amori, PE, RRC

3.  Description  Using negative pressure to simulate and test resistance to wind induced uplift on a membrane roof system.

4.  Test Summary  Test pressures are obtained from the structural engineer and/or governing agency. These usually include field, perimeter, and corner test pressures.  The apparatus is installed and pressure is gradually increased to the test pressure in 7.5 psf increments (held for one minute) while simultaneously recording the deflection of the membrane.  Failure is 0.25 to 0.94 of an inch deflection (FM) and one inch (ASTM).

7.  Test Summary  Failure are typically cut open to make observations regarding the failure mode  Material Failure  Delamination  Fastener Pull  Substrate Failure

8.  Application  Insurability for specific carriers  Factory Mutual  TWIA  Code Compliance  New Construction Design Compliance

9.  Application  Risk Assessment – as part of the evaluation of a property this test is used to determine probable loss at incremental pressure (Hurricane Strengths).

10.  Relevant Standards  ASTM E 907 – 96 (Reapproved 2004): Field Testing Uplift Resistance of Adhered Membrane Roofing Systems  FM Global 1-52: Field Uplift Tests

12. 25 psf ~ 25 psf

13. 25 psf For roof slope < 7 degrees 45 psf 70 psf

24. FASNTERS RESISTING PRESSURE

25. MATERIAL DELAMINATION

26. LACK OF TORCH